Patents by Inventor Avinash K. Gupta
Avinash K. Gupta has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11035054Abstract: In an apparatus and method growing a SiC single crystal, a PVT growth apparatus is provided with a single crystal SiC seed and a SiC source material positioned in spaced relation in a growth crucible. A resistance heater heats the growth crucible such that the SiC source material sublimates and is transported via a temperature gradient that forms in the growth crucible in response to the heater heating the growth crucible to the single crystal SiC seed where the sublimated SiC source material condenses forming a growing SiC single crystal. Purely axial heat fluxes passing through the bottom and the top of the growth crucible form a flat isotherm at least at a growth interface of the growing SiC single crystal on the single crystal SiC seed.Type: GrantFiled: July 1, 2019Date of Patent: June 15, 2021Assignee: II-VI DELAWARE, INC.Inventors: Xueping Xu, Ilya Zwieback, Avinash K. Gupta, Varatharajan Rengarajan
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Publication number: 20190323145Abstract: In an apparatus and method growing a SiC single crystal, a PVT growth apparatus is provided with a single crystal SiC seed and a SiC source material positioned in spaced relation in a growth crucible. A resistance heater heats the growth crucible such that the SiC source material sublimates and is transported via a temperature gradient that forms in the growth crucible in response to the heater heating the growth crucible to the single crystal SiC seed where the sublimated SiC source material condenses forming a growing SiC single crystal. Purely axial heat fluxes passing through the bottom and the top of the growth crucible form a flat isotherm at least at a growth interface of the growing SiC single crystal on the single crystal SiC seed.Type: ApplicationFiled: July 1, 2019Publication date: October 24, 2019Inventors: Xueping Xu, Ilya Zwieback, Avinash K. Gupta, Varatharajan Rengarajan
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Publication number: 20190249332Abstract: A physical vapor transport growth system includes a growth chamber charged with SiC source material and a SiC seed crystal in spaced relation and an envelope that is at least partially gas-permeable disposed in the growth chamber. The envelope separates the growth chamber into a source compartment that includes the SiC source material and a crystallization compartment that includes the SiC seed crystal. The envelope is formed of a material that is reactive to vapor generated during sublimation growth of a SiC single crystal on the SiC seed crystal in the crystallization compartment to produce C-bearing vapor that acts as an additional source of C during the growth of the SiC single crystal on the SiC seed crystal.Type: ApplicationFiled: March 29, 2019Publication date: August 15, 2019Inventors: Avinash K. Gupta, Ilya Zwieback, Edward Semenas, Marcus L. Getkin, Patrick D. Flynn
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Patent number: 10294584Abstract: A physical vapor transport growth system includes a growth chamber charged with SiC source material and a SiC seed crystal in spaced relation and an envelope that is at least partially gas-permeable disposed in the growth chamber. The envelope separates the growth chamber into a source compartment that includes the SiC source material and a crystallization compartment that includes the SiC seed crystal. The envelope is formed of a material that is reactive to vapor generated during sublimation growth of a SiC single crystal on the SiC seed crystal in the crystallization compartment to produce C-bearing vapor that acts as an additional source of C during the growth of the SiC single crystal on the SiC seed crystal.Type: GrantFiled: March 25, 2010Date of Patent: May 21, 2019Assignee: II-VI INCORPORATEDInventors: Avinash K. Gupta, Ilya Zwieback, Edward Semenas, Marcus L. Getkin, Patrick D. Flynn
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Publication number: 20170321345Abstract: In an apparatus and method growing a SiC single crystal, a PVT growth apparatus is provided with a single crystal SiC seed and a SiC source material positioned in spaced relation in a growth crucible. A resistance heater heats the growth crucible such that the SiC source material sublimates and is transported via a temperature gradient that forms in the growth crucible in response to the heater heating the growth crucible to the single crystal SiC seed where the sublimated SiC source material condenses forming a growing SiC single crystal. Purely axial heat fluxes passing through the bottom and the top of the growth crucible form a flat isotherm at least at a growth interface of the growing SiC single crystal on the single crystal SiC seed.Type: ApplicationFiled: May 2, 2017Publication date: November 9, 2017Inventors: Xueping Xu, Ilya Zwieback, Avinash K. Gupta, Varatharajan Rengarajan
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Patent number: 9388509Abstract: In a method of forming polycrystalline SiC grain material, low-density, gas-permeable and vapor-permeable bulk carbon is positioned at a first location inside of a graphite crucible and a mixture of elemental silicon and elemental carbon is positioned at a second location inside of the graphite crucible. Thereafter, the mixture and the bulk carbon are heated to a first temperature below the melting point of the elemental Si to remove adsorbed gas, moisture and/or volatiles from the mixture and the bulk carbon. Next, the mixture and the bulk carbon are heated to a second temperature that causes the elemental Si and the elemental C to react forming as-synthesized SiC inside of the crucible. The as-synthesized SiC and the bulk carbon are then heated in a way to cause the as-synthesized SiC to sublime and produce vapors that migrate into, condense on and react with the bulk carbon forming polycrystalline SiC material.Type: GrantFiled: July 26, 2013Date of Patent: July 12, 2016Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Avinash K. Gupta, Ping Wu, Donovan L. Barrett, Gary E. Ruland, Thomas E. Anderson
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Patent number: 9322110Abstract: A sublimation grown SiC single crystal includes vanadium dopant incorporated into the SiC single crystal structure via introduction of a gaseous vanadium compound into a growth environment of the SiC single crystal during growth of the SiC single crystal.Type: GrantFiled: October 28, 2013Date of Patent: April 26, 2016Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Thomas E. Anderson, Avinash K. Gupta, Michael C. Nolan, Bryan K. Brouhard, Gary E. Ruland
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Patent number: 9090989Abstract: In a crystal growth apparatus and method, polycrystalline source material and a seed crystal are introduced into a growth ambient comprised of a growth crucible disposed inside of a furnace chamber. In the presence of a first sublimation growth pressure, a single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a first gas that includes a reactive component that reacts with and removes donor and/or acceptor background impurities from the growth ambient during said sublimation growth. Then, in the presence of a second sublimation growth pressure, the single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a second gas that includes dopant vapors, but which does not include the reactive component.Type: GrantFiled: May 24, 2013Date of Patent: July 28, 2015Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Ping Wu, Varatharajan Rengarajan, Avinash K. Gupta, Thomas E. Anderson, Gary E. Ruland, Andrew E. Souzis, Xueping Xu
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Patent number: 9017629Abstract: In method of crystal growth, an interior of a crystal growth chamber (2) is heated to a first temperature in the presence of a first vacuum pressure whereupon at least one gas absorbed in a material (4) disposed inside the chamber is degassed therefrom. The interior of the chamber is then exposed to an inert gas at a second, higher temperature in the presence of a second vacuum pressure that is at a higher pressure than the first vacuum pressure. The inert gas pressure in the chamber is then reduced to a third vacuum pressure that is between the first and second vacuum pressures and the temperature inside the chamber is lowered to a third temperature that is between the first and second temperatures, whereupon source material (10) inside the chamber vaporizes and deposits on a seed crystal (12) inside the chamber.Type: GrantFiled: September 27, 2006Date of Patent: April 28, 2015Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Donovan L. Barrett, Avinash K. Gupta
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Patent number: 8858709Abstract: A physical vapor deposition method of growing a crystal includes providing a seed crystal and a source material in spaced relation inside of a growth crucible that is at least in-part gas permeable to an unwanted gas. The growth chamber is heated whereupon the source material sublimates and is transported via a temperature gradient in the growth chamber to the seed crystal where the sublimated source material precipitates. Concurrent with heating the growth chamber, a purging gas is caused to flow inside or outside of the growth crucible in a manner whereupon the unwanted gas flows from the inside to the outside of the growth crucible via the gas permeable part thereof.Type: GrantFiled: April 10, 2007Date of Patent: October 14, 2014Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Avinash K. Gupta
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Publication number: 20140234194Abstract: A sublimation grown SiC single crystal includes vanadium dopant incorporated into the SiC single crystal structure via introduction of a gaseous vanadium compound into a growth environment of the SiC single crystal during growth of the SiC single crystal.Type: ApplicationFiled: October 28, 2013Publication date: August 21, 2014Applicant: II-VI IncorporatedInventors: Ilya Zwieback, Thomas E. Anderson, Avinash K. Gupta, Michael C. Nolan, Bryan K. Brouhard, Gary E. Ruland
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Patent number: 8741413Abstract: A method and system of forming large-diameter SiC single crystals suitable for fabricating high crystal quality SiC substrates of 100, 125, 150 and 200 mm in diameter are described. The SiC single crystals are grown by a seeded sublimation technique in the presence of a shallow radial temperature gradient. During SiC sublimation growth, a flux of SiC bearing vapors filtered from carbon particulates is substantially restricted to a central area of the surface of the seed crystal by a separation plate disposed between the seed crystal and a source of the SiC bearing vapors. The separation plate includes a first, substantially vapor-permeable part surrounded by a second, substantially non vapor-permeable part. The grown crystals have a flat or slightly convex growth interface. Large-diameter SiC wafers fabricated from the grown crystals exhibit low lattice curvature and low densities of crystal defects, such as stacking faults, inclusions, micropipes and dislocations.Type: GrantFiled: April 22, 2013Date of Patent: June 3, 2014Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Thomas E. Anderson, Andrew E. Souzis, Gary E. Ruland, Avinash K. Gupta, Varatharajan Rengarajan, Ping Wu, Xueping Xu
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Publication number: 20130320275Abstract: In a crystal growth apparatus and method, polycrystalline source material and a seed crystal are introduced into a growth ambient comprised of a growth crucible disposed inside of a furnace chamber. In the presence of a first sublimation growth pressure, a single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a first gas that includes a reactive component that reacts with and removes donor and/or acceptor background impurities from the growth ambient during said sublimation growth. Then, in the presence of a second sublimation growth pressure, the single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a second gas that includes dopant vapors, but which does not include the reactive component.Type: ApplicationFiled: May 24, 2013Publication date: December 5, 2013Inventors: Ilya Zwieback, Ping Wu, Varatharajan Rengarajan, Avinash K. Gupta, Thomas E. Anderson, Gary E. Ruland, Andrew E. Souzis, Xueping Xu
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Publication number: 20130309496Abstract: In a method of forming polycrystalline SiC grain material, low-density, gas-permeable and vapor-permeable bulk carbon is positioned at a first location inside of a graphite crucible and a mixture of elemental silicon and elemental carbon is positioned at a second location inside of the graphite crucible. Thereafter, the mixture and the bulk carbon are heated to a first temperature below the melting point of the elemental Si to remove adsorbed gas, moisture and/or volatiles from the mixture and the bulk carbon. Next, the mixture and the bulk carbon are heated to a second temperature that causes the elemental Si and the elemental C to react forming as-synthesized SiC inside of the crucible. The as-synthesized SiC and the bulk carbon are then heated in a way to cause the as-synthesized SiC to sublime and produce vapors that migrate into, condense on and react with the bulk carbon forming polycrystalline SiC material.Type: ApplicationFiled: July 26, 2013Publication date: November 21, 2013Applicant: II-VI IncorporatedInventors: Ilya Zwieback, Avinash K. Gupta, Ping Wu, Donovan L. Barrett, Gary E. Ruland, Thomas E. Anderson
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Publication number: 20130280466Abstract: A method and system of forming large-diameter SiC single crystals suitable for fabricating high crystal quality SiC substrates of 100, 125, 150 and 200 mm in diameter are described. The SiC single crystals are grown by a seeded sublimation technique in the presence of a shallow radial temperature gradient. During SiC sublimation growth, a flux of SiC bearing vapors filtered from carbon particulates is substantially restricted to a central area of the surface of the seed crystal by a separation plate disposed between the seed crystal and a source of the SiC bearing vapors. The separation plate includes a first, substantially vapor-permeable part surrounded by a second, substantially non vapor-permeable part. The grown crystals have a flat or slightly convex growth interface. Large-diameter SiC wafers fabricated from the grown crystals exhibit low lattice curvature and low densities of crystal defects, such as stacking faults, inclusions, micropipes and dislocations.Type: ApplicationFiled: April 22, 2013Publication date: October 24, 2013Inventors: Ilya Zwieback, Thomas E. Anderson, Andrew E. Souzis, Gary E. Ruland, Avinash K. Gupta, Varatharajan Rengarajan, Ping Wu, Xueping Xu
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Patent number: 8512471Abstract: In a physical vapor transport growth technique for silicon carbide a silicon carbide powder and a silicon carbide seed crystal are introduced into a physical vapor transport growth system and halosilane gas is introduced separately into the system. The source powder, the halosilane gas, and the seed crystal are heated in a manner that encourages physical vapor transport growth of silicon carbide on the seed crystal, as well as chemical transformations in the gas phase leading to reactions between halogen and chemical elements present in the growth system.Type: GrantFiled: May 15, 2012Date of Patent: August 20, 2013Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Thomas E. Anderson, Avinash K. Gupta
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Patent number: 8361227Abstract: In a crystal growth method, an enclosed growth crucible is provided inside of a growth chamber. The growth crucible has polycrystalline source material and a seed crystal disposed in spaced relation therein. The interior of the growth crucible is heated whereupon a temperature gradient forms between the source material and the seed crystal. The temperature gradient is sufficient to cause the source material to sublimate and be transported to the seed crystal where it precipitates on the seed crystal. A gas mixture is caused to flow into the growth crucible and between the polycrystalline source material and an interior surface of the growth crucible. The gas mixture reacts with an unwanted element in the body of the growth crucible to form a gaseous byproduct which then flows through the body of the growth crucible to the exterior of the growth crucible.Type: GrantFiled: September 11, 2007Date of Patent: January 29, 2013Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Thomas E. Anderson, Avinash K. Gupta
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Patent number: 8313720Abstract: In the growth of a SiC boule, a growth guide is provided inside of a growth crucible that is charged with SiC source material at a bottom of the crucible and a SiC seed crystal at a top of the crucible. The growth guide has an inner layer that defines at least part of an opening in the growth guide and an outer layer that supports the inner layer in the crucible. The opening faces the source material with the seed crystal positioned at an end of the opening opposite the source material. The inner layer is formed from a first material having a higher thermal conductivity than the second, different material forming the outer layer. The source material is sublimation grown on the seed crystal in the growth crucible via the opening in the growth guide to thereby form the SiC boule on the seed crystal.Type: GrantFiled: January 15, 2008Date of Patent: November 20, 2012Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Avinash K. Gupta, Edward Semenas, Thomas E. Anderson
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Patent number: RE46315Abstract: A method and system of forming large-diameter SiC single crystals suitable for fabricating high crystal quality SiC substrates of 100, 125, 150 and 200 mm in diameter are described. The SiC single crystals are grown by a seeded sublimation technique in the presence of a shallow radial temperature gradient. During SiC sublimation growth, a flux of SiC bearing vapors filtered from carbon particulates is substantially restricted to a central area of the surface of the seed crystal by a separation plate disposed between the seed crystal and a source of the SiC bearing vapors. The separation plate includes a first, substantially vapor-permeable part surrounded by a second, substantially non vapor-permeable part. The grown crystals have a flat or slightly convex growth interface. Large-diameter SiC wafers fabricated from the grown crystals exhibit low lattice curvature and low densities of crystal defects, such as stacking faults, inclusions, micropipes and dislocations.Type: GrantFiled: October 6, 2014Date of Patent: February 21, 2017Assignee: II-VI IncorporatedInventors: Ilya Zwieback, Thomas E. Anderson, Andrew E. Souzis, Gary E. Ruland, Avinash K. Gupta, Varatharajan Rengarajan, Ping Wu, Xueping Xu
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Patent number: RE48378Abstract: In a crystal growth apparatus and method, polycrystalline source material and a seed crystal are introduced into a growth ambient comprised of a growth crucible disposed inside of a furnace chamber. In the presence of a first sublimation growth pressure, a single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a first gas that includes a reactive component that reacts with and removes donor and/or acceptor background impurities from the growth ambient during said sublimation growth. Then, in the presence of a second sublimation growth pressure, the single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a second gas that includes dopant vapors, but which does not include the reactive component.Type: GrantFiled: May 1, 2017Date of Patent: January 5, 2021Assignee: II-VI Delaware, Inc.Inventors: Ilya Zwieback, Ping Wu, Varatharajan Rengarajan, Avinash K. Gupta, Thomas E. Anderson, Gary E. Ruland, Andrew E. Souzis, Xueping Xu